An update for anyone who is searching the Internet to solve similar problems. I eventually replaced all of the components in my old PC build, until none of the original parts were left. It was only after switching out the CPU that these problems went away. I thought I had tested the CPU...
Built my first desktop computer a little over 2 years ago and haven't had any problems with it until recently. A few months back I noticed some strange behavior that has made my PC basically unusable.
This includes pixelated/distorted online images and "chirping" audio when streaming videos...